Sony Ericsson HBH-608 Replacement Battery 3.7V 140mAh

Sony Ericsson HBH-608 — 3.7V Li-Polymer Replacement Battery

This is a 3.7V, 140mAh Li-Polymer battery for the Sony Ericsson HBH-608 Bluetooth mono headset. It replaces the original cell when charge retention has dropped to the point where the headset no longer completes calls. Dimensions are 31.83 × 11.03 × 4.00mm — a direct physical match to the original cell cavity.

• HBH-608 fit: The HBH-608 runs a single Li-Polymer cell at 3.7V nominal. This battery matches that voltage rail and physical footprint. The onboard BMS in the headset reads cell state on connection — voltage must sit within the expected range for the headset to power on at all.
• Bench tested on actual hardware: We cycled this cell through the HBH-608's charge and discharge circuit. The BMS accepted the cell without error, and charge current tapered correctly at full capacity. No voltage spike or cutoff anomaly was recorded during the test.
• First charge on the HBH-608: Charge the headset in its cradle for a complete cycle before making a call. The headset's talk-time counter calibrates against the cell during the first full charge — skipping this step produces a misread state-of-charge from the start.

Talk time shorter than rated on the first few cycles

A fresh Li-Polymer cell does not hit rated capacity on cycle one. Electrochemical activation across the polymer electrolyte takes three to five charge-discharge cycles to stabilise. On the HBH-608, this shows as a shorter-than-expected session before the low-battery tone. Run the headset through at least three full cycles before drawing any conclusions about capacity. By cycle five, output should be at or near the 140mAh rating.

Headset cuts out mid-call even with a new battery installed

The HBH-608 draws from the cell simultaneously for audio processing and the Bluetooth radio — combined load that spikes during transmission bursts. If the replacement cell was stored for an extended period and shipped at storage voltage, the BMS may trigger a low-voltage cutoff under that combined draw before a full charge has been completed. The fix is straightforward: charge the headset to 100% before the first use. If cutouts persist after a full charge cycle, check that the cell contacts in the headset housing are clean and seated flat — a partial contact raises internal resistance enough to cause voltage sag under load.